Method TableUpdateBorders

KBotExt/imgui/imgui_tables.cpp:1175–1234

Process hit-testing on resizing borders. Actual size change will be applied in EndTable() - Set table->HoveredColumnBorder with a short delay/timer to reduce visual feedback noise.

// Process hit-testing on resizing borders. Actual size change will be applied in EndTable()
// - Set table->HoveredColumnBorder with a short delay/timer to reduce visual feedback noise.
void ImGui::TableUpdateBorders(ImGuiTable* table)
{
	ImGuiContext& g = *GImGui;
	IM_ASSERT(table->Flags & ImGuiTableFlags_Resizable);

	// At this point OuterRect height may be zero or under actual final height, so we rely on temporal coherency and
	// use the final height from last frame. Because this is only affecting _interaction_ with columns, it is not
	// really problematic (whereas the actual visual will be displayed in EndTable() and using the current frame height).
	// Actual columns highlight/render will be performed in EndTable() and not be affected.
	ImGuiTableInstanceData* table_instance = TableGetInstanceData(table, table->InstanceCurrent);
	const float hit_half_width = TABLE_RESIZE_SEPARATOR_HALF_THICKNESS;
	const float hit_y1 = table->OuterRect.Min.y;
	const float hit_y2_body = ImMax(table->OuterRect.Max.y, hit_y1 + table_instance->LastOuterHeight);
	const float hit_y2_head = hit_y1 + table_instance->LastFirstRowHeight;

	for (int order_n = 0; order_n < table->ColumnsCount; order_n++)
	{
		if (!IM_BITARRAY_TESTBIT(table->EnabledMaskByDisplayOrder, order_n))
			continue;

		const int column_n = table->DisplayOrderToIndex[order_n];
		ImGuiTableColumn* column = &table->Columns[column_n];
		if (column->Flags & (ImGuiTableColumnFlags_NoResize | ImGuiTableColumnFlags_NoDirectResize_))
			continue;

		// ImGuiTableFlags_NoBordersInBodyUntilResize will be honored in TableDrawBorders()
		const float border_y2_hit = (table->Flags & ImGuiTableFlags_NoBordersInBody) ? hit_y2_head : hit_y2_body;
		if ((table->Flags & ImGuiTableFlags_NoBordersInBody) && table->IsUsingHeaders == false)
			continue;

		if (!column->IsVisibleX && table->LastResizedColumn != column_n)
			continue;

		ImGuiID column_id = TableGetColumnResizeID(table, column_n, table->InstanceCurrent);
		ImRect hit_rect(column->MaxX - hit_half_width, hit_y1, column->MaxX + hit_half_width, border_y2_hit);
		ItemAdd(hit_rect, column_id, NULL, ImGuiItemFlags_NoNav);
		//GetForegroundDrawList()->AddRect(hit_rect.Min, hit_rect.Max, IM_COL32(255, 0, 0, 100));

		bool hovered = false, held = false;
		bool pressed = ButtonBehavior(hit_rect, column_id, &hovered, &held, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnDoubleClick | ImGuiButtonFlags_NoNavFocus);
		if (pressed && IsMouseDoubleClicked(0))
		{
			TableSetColumnWidthAutoSingle(table, column_n);
			ClearActiveID();
			held = hovered = false;
		}
		if (held)
		{
			if (table->LastResizedColumn == -1)
				table->ResizeLockMinContentsX2 = table->RightMostEnabledColumn != -1 ? table->Columns[table->RightMostEnabledColumn].MaxX : -FLT_MAX;
			table->ResizedColumn = (ImGuiTableColumnIdx)column_n;
			table->InstanceInteracted = table->InstanceCurrent;
		}
		if ((hovered && g.HoveredIdTimer > TABLE_RESIZE_SEPARATOR_FEEDBACK_TIMER) || held)
		{
			table->HoveredColumnBorder = (ImGuiTableColumnIdx)column_n;
			SetMouseCursor(ImGuiMouseCursor_ResizeEW);
		}